Module: CalculateAll::Helpers

Defined in:
lib/calculate-all.rb

Overview

module just to not pollute namespace

Class Method Summary collapse

Class Method Details

.decode_expression_shortcut(shortcut, group_values = []) ⇒ Object

Convert shortcuts like :count_distinct_id to SQL aggregate functions like ‘COUNT(DISTINCT ID)’ If shortcut is actually one of the grouping expressions, just return it as-is.



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# File 'lib/calculate-all.rb', line 79

def decode_expression_shortcut(shortcut, group_values = [])
  case shortcut
  when String
    shortcut
  when *group_values
    shortcut
  when :count
    "COUNT(*)"
  when /^(\w+)_distinct_count$/, /^count_distinct_(\w+)$/
    "COUNT(DISTINCT #{$1})"
  when /^(\w+)_(count|sum|max|min|avg)$/
    "#{$2.upcase}(#{$1})"
  when /^(count|sum|max|min|avg)_(\w+)$/
    "#{$1.upcase}(#{$2})"
  when /^(\w+)_average$/, /^average_(\w+)$/
    "AVG(#{$1})"
  when /^(\w+)_maximum$/, /^maximum_(\w+)$/
    "MAX(#{$1})"
  when /^(\w+)_minimum$/, /^minimum_(\w+)$/
    "MIN(#{$1})"
  else
    raise ArgumentError, "Can't recognize expression shortcut #{key}"
  end
end